1. A person who is considered strange to other people. This person may do strange things, so this person can be considered a "weirdo".
2. A non-comformist who does not follow trends or a subculture. A true 'weirdo' will juat do what they feel, and can get along with most people. This person does not actually conform to a stereotype and shouldn't be labled.

1. Eww, he dunks his chicken nuggets in milk and hawks loogies. What a weirdo.
2. She listens to 80's music and wears tye-dye. What a weirdo.